In the tech world, as in just about any other sphere, there are certain myths, campfire stories and old wives’ tales that get passed down and repeated until they transform themselves into indestructible kernels of well-worn wisdom. You know the type of “facts” I’m talking about: You can’t quite remember the source, but you “heard it on TV” or “read it on the Internet” or “one of your friends told you” it was true, or else it seems so obvious, and you’ve known it for so long, that it must be accurate.

And then YOU tell YOUR friends, and the myth rolls on, forever and ever, into the future.

Here, we’re going to examine and disprove 9 of the biggest whoppers in tech — the lies, misunderstandings, fables, and folk tales that we hear over and over again but are simply not true. Hopefully, with a little bit of education, we can start to put an end to some of these persistent tech myths and make the world a little less misinformed.

Let’s do some debunking, shall we? Away we go!

1.) Macs Don’t Get Viruses

For many years, Apple claimed on its website that its computers were better than Windows machines since they weren’t susceptible to viruses like PCs were. Sharks don’t get cancer, real men don’t eat quiche and Apple computers don’t get viruses.

When asked why his speakers, whose volume count went to 11 rather than the traditional 10, were superior to other speakers, Spinal Tap lead guitarist Nigel Tufnel chewed his gum, thought about it for a moment, and then responded, “Well, it’s one louder, isn’t it?” before famously concluding, “These go to 11.”

It was nonsense, and so is the idea that the higher the megapixel count on a camera, the better that camera is. Just because a camera goes “one louder” than another does not mean it will give you better photos.

A higher megapixel count is important if you plan on blowing up a photo to a larger size and don’t want to lose quality (CNET explains), but for normal viewing, megapixels aren’t as important as having a quality camera lens and light sensor.

More goes into a camera than just megapixels, and you shouldn’t be making your digital camera or smartphone selection based solely on the number of MPs it boasts (Gizmodo has a nice, human explanation of why “megapixels don’t matter”). Photography is more nuanced than a round number. There are better ways to get that “extra push over the cliff” (as Tufnel puts it) than increasing your megapixels.

CORRECTION: A previous version of this article stated that Nigel Tufnel was the lead singer of Spinal Tap. David St. Hubbins is, in fact, the lead singer of Spinal Tap; Tufnel plays guitar.

3.) Closing Out Apps On Your iPhone Extends Battery Life

For a long time, the common wisdom held that in order to save battery life on the iPhone, we could just double-tap the home button and close out all the apps on the bottom tray that we weren’t using. BLOOP BLOOP BLOOP: ‘X’ out of the apps, and battery would be saved.

Except, here’s the thing: Those apps you see when you press the home button twice aren’t actually running or using up any battery. As Fraser Speirs pointed out earlier this year, that row of icons is a list of recently used apps, NOT currently-running apps; when you hit the home button and exit an app, the iPhone automatically shuts it down after five seconds or so. Except in special cases (listed on Speirs’ site), the app is not running nor eating up battery life.

Closing out apps might be dang satisfying — it’s like playing whack-a-mole! — but it is almost certainly not preserving battery life.

i work at my desk, so my laptop is plugged in even when I am not using it. Is it true this ruins the battery? If that is the case, should i remove the battery when i am not using it??

The short answer (which the top respondent got correct!): No, you are not ruining your laptop battery by keeping it on charge, unless your laptop is very, very old.

This myth may have been true of nickel-based laptop batteries, which laptops and smartphones seldom use anymore; most laptops nowadays, however, use lithium-based batteries, which are not susceptible to “losing charge” if you keep them plugged in all the time. In fact, it’s probably better to stay plugged in than it is to constantly drain your battery to zero percent and then recharge over and over again, an act that lowers your battery’s lifespan.

5.) You Need To Run Down Your Battery All The Way At Least Once A Week, Perhaps More

Again, this is an old bit of wisdom applied erroneously to new technologies. Your lithium-ion battery is only good for so many “cycles,”according to long-time tech writer Daniel Rutter. Allowing your battery to drop to 10 percent and then recharging counts as a cycle, wears on the battery, and reduces its longevity. It’s not something you want to do too often, unless you really enjoy battery shopping.

Watch out, guys: Your laptop is literally zapping your sperm one by one, like Marvin the Martian with a vendetta against your little guys. I can understand why this scary story — in which a team of researchers found that sperm exposed to radiation from laptop WiFi had badly damaged DNA and were less motile — might make men think twice about holding their laptops on their laps, unless they were wearing some kind of radiation-blocking iron jockstrap (and really, who doesn’t?). But it now appears that the study was carelessly carried out and likely did not indicate that our sperm was in danger in a real-world setting.

Here’s Dr. Robert Oates, President of the Society for Male Reproduction and Urology, debunking the findings in Reuters: “This is not real-life biology, this is a completely artificial setting…It is scientifically interesting, but to me it doesn’t have any human biological relevance.”

There are plenty of good reasons not to hold your laptop on your lap: The descriptively named “toasted skin syndrome” or “laptop thigh” (DO NOT GOOGLE) being one of them — but an evisceration of your sperm by the notebook’s WiFi signal is not one of them. You, and your semen, can rest safe.

7.) The QWERTY Keyboard Was Designed To Slow Typists Down

A lot of keyboard elitists — yes, they exist, mostly in Portland — will try to claim to you that the QWERTY layout was so designed in order to slow down typists and that only simpletons still use QWERTY, the sophisticated herd having switched over to the DVORAK layout. But hold your head high, QWERTY user: It isn’t true, at all. The (incorrect) story goes that back in the early days of the typewriter, in the 1870s, a newspaper editor was tired of how often his reporters’ typewriters kept jamming, so he conspired to configure the keys to be so idiotically placed with respect to one another that even the nimblest typists would be slowed down and jams would be reduced.

A pretty story but — alas! — not true. The QWERTY layout was decided upon in order to reduce jams, but not by making the act of typing slower. Instead, as this helpful article explains, the keys were laid out according to a combination of letter frequency and so that hitting common letter combinations — “t” and “h,” for example — would not cause internal jammage. Thus was born the modern keyboard, which just so happened to have the letters Q-W-E-R-T-Y in order across the top row. In the 1930s, a new keyboard was invented: the DVORAK, which put the five most frequently used vowels and the five most frequently used consonants in the middle row. By then, however, the QWERTY had such a strong foothold that it would continue to be the default keyboard for decades to come (except in Williamsburg, Brooklyn, where I hear DVORAK’s huge).

8.) A Magnet Can And Will Erase Your Hard Drive

Magnets: How do they work? It’s a sincere mystery to most, but this much we do know: Unless you keep some ridiculously powerful degaussing magnets in your home, you’re probably not going to zap your hard drive with one.

PCWorld debunked this one all the way back in 2004: Though a common magnet can erase the contents of a floppy disk (remember those?), USB storage, SD cards, and laptop and desktop hard drives are safe from all but the very strongest magnets. In more detail, meanwhile,PCMag attempted to find out what it would take to use a magnet to erase a laptop’s hard drive without removing it: The magazine found that you would need an incredibly strong, industrial-strength magnet pointed in just the right direction in order to wipe a hard drive’s contents, and that it was about as unlikely as my getting a date to junior prom (really, really unlikely).

In other words, your data is probably A-OK if you accidentally place a refrigerator magnet on your MacBook. Better safe than sorry, of course — you shouldn’t keep magnets near your hard drive, nor your laptop near your sperm, nor magnets near your sperm, etc. — but it’s still not likely you’re going to wipe your memory with any magnet you keep at home.

9.) Facebook Is About To Start Charging For Service

No, it isn’t. Don’t believe the chain letters, or your great uncle’s alarmist status, or whatever. Facebook is never going to charge for service.